1. Field of Invention
The present invention relates to electrical heating devices, and more particularly, relates to a kind of relay switch used for toaster.
2. Description of Related Arts
For lots of people, the toaster is a daily part of breakfast. Commonly, an electrical toaster comprises an outer casing, a handle, a base, an electrical timer, and a PCB module. The basic idea behind the toaster is simple. A toaster uses infrared radiation to heat a piece of bread. When a user put a piece of bread in and sees the coils glow red, the coils would produce infrared radiation to dry and char the surface of the bread. The timer is adapted to set a toasting time, turn the toaster off automatically after the preset time runs up and at the same time releases the tray so that toasted bread pops up. Accordingly, a user is able to freely and selectively set the toasting time according to his preference of toast darkness.
Ordinarily, an electrical toaster is operated in the following procedure. Above all, a user would ensure the toaster is electrically powered; afterwards, he or she would insert the bread into the bread compartment of the toaster, such that the bread could be supported by a toasting tray and a sliding rack which is coupled to the handle of the toaster. After then, the user would set a desirable toasting time by adjusting the timer. By depressing down the handle, the sliding rack and toasting tray would be lowered into the bread compartment, and simultaneously, the lowered toasting tray would press against the contact enabling the switch to be electrically powered to charge the electromagnet of the timer thus attracting the engaging metal (commonly a piece of metal) in position. During such position, the switch is maintained at a power-on status, the handle, the sliding rack and the toasting tray is kept at the same position. As a result, the coils would be enabled to heat and toast the bread. Whenever the toasting time reach the preset toasting time in practice, the electromagnet of the timer would be powered off for releasing the engaging metal. As a result, the spring-loaded toasting tray coupled to the engaging metal would be pop up to resume a default upper position.
However, occasionally due to some accidental factors, the automatic urging mechanism of the toasting tray might fail to rebound in practice. For example, the sliding rack and the toasting tray could have been stuck within the casing and failed to pop up. The consequences of such failure would be devastating. This is due to the fact that the switch of the power source could not be severed off; the coils would be powered for an extended period of time thus singing the bread as well as resulting accidents and personal harms. This overtime toasting would cause over-baked bread useless, even bring serious damage to components of the electrical toaster allowing users in a dangerous position.
Additionally, the electromagnet and the engaging metal are exposed without any protection arrangement. Meanwhile, the contact of power source would generate sparks as well as electric arc in practice, which would be considered as potential danger. Finally, the crumb as well as dust would contaminate the electrical switch thus invalidating the performance of the electromagnet and the engaging metal.